Typically, power tools, such as polishers or waxers, for use on delicate work surfaces of varying contours, including exterior car finishes, tend to lack a structure, e.g., handles, that allow for effective and precise operator control and maneuverability during operation on the surface. Such power tools commonly include a motor that drives a working element, such as a polishing or waxing pad, in an orbital path for engagement with the work surface. To properly treat the work surface while preventing damage thereto, it is important that an operator be able to precisely guide the working element along the work surface and to simultaneously control the pressure with which the working element is applied to the work surface. For instance, if the tool is used with too much pressure, such as by not being able to control and prevent the entire weight of the tool from being applied to the working element and, consequently, the work surface, the finish on the work surface can be easily damaged or even ruined. On the other hand, too little application pressure will tend to result in the surface finish not being polished properly or in an increase in operation time to accomplish the desired finish.
The vibratory response associated with orbital motion further complicates the polishing operations. It has been found that such response felt by operators using orbital motion is significantly greater than that associated with other non-orbital type tools. Thus, the structure of the power tool must take into consideration this response.
To increase efficiency, it is also desirable that an operator be able cover a relatively large area on the work surface, while at the same time maintaining control over the application pressure and path of the tool during operation. This is usually accomplished by either relocating to a different location relative to the work surface or by extending one's arms over and about the work surface. The latter technique is used most often when polishing remote areas that cannot be accessed by simply relocating, such as when polishing central areas of an automobile, e.g., central areas of the hood, roof and trunk. As mentioned above, experience, however, has taught that accuracy and precision is sacrificed when operating the tool with one's arms extended because of the increased vibrational response from orbital motion.
Another problem in operation of these tools is the location of the power supply line providing power to the motor. Oftentimes, such electrical cord is connected either directly, or with a pigtail cord, to the housing. These power cords tend to increase the likelihood of damage to the working surface due to it and its associated connecting head coming in contact with such surface and any wax thereon during operation of the polisher. This is undesirable due to potential marring of the finish caused by such contact.
Pigtail cords also present the additional problem that when the work surface is close to the ground, such as the lower portions of a car's exterior surface, the mating interface between the heads of the pigtail and the power supplying cord can run along the ground, potentially through any standing water accumulated thereon, which can present a hazardous situation to the operator. If the water causes a ground fault, the power to the tool will be abruptly interrupted, which can cause damage to both the power tool and the surface in engagement with the tool.
Also, normally the cord is in a position relative to the handle such that operators are required to continually adjust their support of the tool and grip on the handle(s) during operation of the tool due to undue interference from the power supplying cord.
With pigtail cords, as well as with cords connected directly to an electrical receptacle on the housing, there exits a concern with accidental separation between the pigtail or the receptacle and the supply cord. Separation problems are compounded with orbital polishers and waxers as typically they are used with car surfaces which can require an operator to move around the automobile to buff or wax the entire extent of its exterior surfaces. Such movement can cause tension to be applied to the interface between the electrical supply cord and the tool, be it on the head of a pigtail cord attached to the housing or at an electrical receptacle at the housing itself. In addition, the increased levels of vibration generated through the polisher housing increases the potential for separation as the cord(s) are constantly experiencing intermittent tension forces.
Thus, there is a need for a power tool, particularly one that drives its working element in an orbital path, which allows an operator to effectively and accurately control the working element and reach a relatively large area on a working surface from a generally stationary position. There is also a need for an ergonomic power tool as described above which removes the electrical connection or power cord as an impediment to control and operation of the tool and substantially limits disconnections at the interface between the power supply and power receiving receptacle of the tool.
Further, with power waxers, the working element typically includes a circular pad that is driven by the electric motor in a somewhat random orbital path so as to simulate the orbital motion made by a person waxing with a rag or cloth by hand. These pads commonly have a foam construction and are not designed to be placed into engagement with the working surface for polishing. Instead, the pad is fitted with a bonnet that is elastically fitted about the pad and is designed for polishing contact with the working surface.
Bonnets of varying material are used for different stages in the polishing process, including wax application, polishing and buffing stages. In a common process, paste or liquid wax is first applied onto an applicator bonnet fitted on the pad for spreading the wax on the work surface. Once the surface is covered with wax, the wax applicator bonnet is removed from the pad and a clean terry cloth bonnet is fitted on the pad for polishing the wax on the work surface. Finally, the surface is buffed to produce a deep shine by placing more pressure on the surface with the pad assembly as the waxer is operated and/or replacing the polishing pad with a bonnet, such as of lambs wool, which creates more friction on the wax surface.
Without being able to quickly change the bonnets, operators would be required to adjust the force applied by the pad assembly on the surface during each stage of the polishing operation. For instance, without changing bonnets, each subsequent stage would require additional pressure, which can lead to mistakes and in many cases damage to the work surfaces. Accordingly, it would be desirable to provide a waxer that allows operators to readily change bonnets to more precisely apply the appropriate force during the various stages during the polishing process.
As discussed in commonly assigned U.S. Pat. No. 5,642,008, power waxers typically use a direct current motor assembly with a rectifier to convert alternating current into direct current for application to the coils of the direct current motor. Another problem lies in the construction of the rectifiers themselves that have elongated blade terminals which extend into and out from the body of the rectifiers. The use of blade terminals adds costs to the manufacture of these rectifiers. Another expense arises with respect to the electrical connections that are necessary between the rectifier and the motor circuitry. Accordingly, a less expensive rectifier for use with a direct current motor for a power tool, and particularly a waxer would be desirable.